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Zerouali Y.,University of Quebec | Herry C.L.,University of Quebec | Jemel B.,University of Montreal | Jemel B.,Fernand Seguin Research Center | And 2 more authors.
IEEE Transactions on Biomedical Engineering | Year: 2013

Neural synchronization is a key mechanism to a wide variety of brain functions, such as cognition, perception, or memory. High temporal resolution achieved by EEG recordings allows the study of the dynamical properties of synchronous patterns of activity at a very fine temporal scale but with very low spatial resolution. Spatial resolution can be improved by retrieving the neural sources of EEG signal, thus solving the so-called inverse problem. Although many methods have been proposed to solve the inverse problem and localize brain activity, few of them target the synchronous brain regions. In this paper, we propose a novel algorithm aimed at localizing specifically synchronous brain regions and reconstructing the time course of their activity. Using multivariate wavelet ridge analysis, we extract signals capturing the synchronous events buried in the EEG and then solve the inverse problem on these signals. Using simulated data, we compare results of source reconstruction accuracy achieved by our method to a standard source reconstruction approach. We show that the proposed method performs better across a wide range of noise levels and source configurations. In addition, we applied our method on real dataset and identified successfully cortical areas involved in the functional network underlying visual face perception. We conclude that the proposed approach allows an accurate localization of synchronous brain regions and a robust estimation of their activity. © 2013 IEEE.

Fleury M.-J.,McGill University | Grenier G.,Douglas Hospital Research Center | Lesage A.,McGill University | Ma N.,Fernand Seguin Research Center | Ngui A.N.,Douglas Hospital Research Center
International Journal of Integrated Care | Year: 2014

Introduction: We know little about the intensity and determinants of interorganisational collaboration within the homeless network. This study describes the characteristics and relationships (along with the variables predicting their degree of interorganisational collaboration) of 68 organisations of such a network in Montreal (Quebec, Canada). Theory and methods: Data were collected primarily through a self-administered questionnaire. Descriptive analyses were conducted followed by social network and multivariate analyses. Results: The Montreal homeless network has a high density (50.5%) and a decentralised structure and maintains a mostly informal collaboration with the public and cross-sectorial sectors. The network density showed more frequent contacts among four types of organisations which could point to the existence of cliques. Four variables predicted interorganisational collaboration: organisation type, number of services offered, volume of referrals and satisfaction with the relationships with public organisations. Conclusions and discussion: The Montreal homeless network seems adequate to address non-complex homelessness problems. Considering, however, that most homeless individuals present chronic and complex profiles, it appears necessary to have a more formal and better integrated network of homeless organisations, particularly in the health and social service sectors, in order to improve services.

Poirier-Bisson J.,University of Quebec at Montreal | Marchand A.,University of Quebec at Montreal | Marchand A.,Fernand Seguin Research Center | Pelland M.-E.,University of Quebec at Montreal | And 4 more authors.
Journal of Nervous and Mental Disease | Year: 2013

The aim of this study was to assess the incremental cost-effectiveness ratios (ICERs) of two brief cognitive-behavioral therapy (CBT)-based interventions and a pharmacological treatment, compared with usual care, initiated in the emergency department (ED) for individuals with panic disorder (PD) with a chief complaint of noncardiac chest pain. A total of 69 patients were followed up to 6 months. The primary outcome variables were direct and indirect costs of treatment and PD severity. Panic management (PM) had an ICER of $124.05, per the Anxiety Disorders Interview Schedule for Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition, severity score change (95% confidence interval [CI], $54.63-$314.57), compared with pharmacotherapy (paroxetine), with an ICER of $213.90 (95% CI, $133.51-$394.94), and brief CBT, with an ICER of $309.31 (95% CI, $151.27-$548.28). The pharmacological and CBT interventions were associated with a greater clinical improvement compared with usual care at posttest. PM presented a superior ICER, suggesting that it may be a promising treatment option to implement in EDs. Copyright © 2013 Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited.

Dumais A.,University of Montreal | Cote G.,University of Quebec at Trois - Rivieres | Cote G.,Philippe Pinel Institute of Montreal | Lesage A.,Fernand Seguin Research Center | Lesage A.,University of Montreal
Canadian Journal of Psychiatry | Year: 2010

Objective: To identify the clinical specificity of men with severe mental illness (aged 18 to 40 years) by legal status. Method: Our study compared 85 inmates with 66 involuntarily hospitalized patients (IHPs) and 50 voluntarily hospitalized patients (VHPs) with at least one Axis I diagnosis of psychosis or major affective disorder. Sociodemographics, medical information, and criminal history were drawn from interviews, medical records, and official criminal records. We used the Structured Clinical Interview for the Diagnostic and Statistical Manual of Mental Disorders to determine Axis I disorders and antisocial personality disorder (ASPD). Psychopathy was measured with the Psychopathy Checklist - Revised. Results: We found that inmates had a lower level of schooling (P = 0.001), were more likely to have been in an intimate relationship (P < 0.001), and were less likely to have a psychiatric hospitalization history (P < 0.001), compared with hospitalized patients. Inmates were also more likely to meet criteria for delusional disorders or psychosis not otherwise specified (P < 0.001) and major depression (P = 0.001). IHPs were more likely to meet schizophrenia spectrum disorder criteria (P < 0.001). Inmates had a higher level of comorbidity involving ASPD (P < 0.001), psychopathy (P < 0.001), and substance misuse (P < 0.001). IHPs showed an intermediate level between inmates and VHPs for these comorbid disorders. VHPs had the lowest level of comorbidity with Axis I psychiatric diagnosis. Conclusion: Our clinical specificity hypothesis was supported: different psychopathological characteristics and social functioning profiles were identified by legal status. Specific integrated treatments should be considered for inmates and IHPs.

O'Connor K.,Fernand Seguin Research Center
Journal of Consciousness Studies | Year: 2012

Obsessive compulsive disorder (OCD) is a debilitating psychiatric condition where people become obsessed by remotely possible harm, error, bad luck, and compulsively repeat mental or behavioural rituals to neutralize these possibilities. This tendency to draw inferences on the basis of remote rather than more likely possibilities is termed 'inferential confusion'and can lead to immersion in possible worlds accompanied by feelings of dissociation between: knowing and doing, imagination and reality, and authentic and inauthentic self. These dissociation experiences in OCD may inform us on the relational 'possibilistic' nature of consciousness. In a relational model of consciousness, the boundaries of consciousness are located between the person and the world, and shift according to the 'aboutness' of self-world interaction. A key element of 'aboutness' is projecting into the future to what is 'about to be', so sense of reality is constructed through a consensus about what could be, operation-alized as a personal possibility distribution. Experiences such as derealization and depersonalization occur in OCD when there is a clash between personally possible worlds and the person ends up living in simultaneously a possible and an impossible world. Recognizing this confusion may be a key to alleviating dissociative symptoms. ©Imprint Academic 2011.

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